Reactor

Reactor is a AI Infrastructure startup based in San Francisco, CA, United States that has raised $59M in venture capital across 1 funding round since 2025. The company reached Series A stage in May 2026 with a $59M round led by Lightspeed Venture Partners. Reactor's investor base includes 6 institutional funds, with Lightspeed Venture Partners leading the most recent equity round.

Reactor is a San Francisco-based developer platform for real-time generative AI video and world models, building the infrastructure layer that makes interactive AI applications practical at scale. The platform abstracts GPU provisioning and infrastructure complexity through a unified SDK and API, delivering sub-50ms frame latency for production workloads. Unlike conventional text-to-video systems that can take up to 10 minutes to produce 10 seconds of output, Reactor's architecture is designed for near-zero time-to-first-frame — enabling use cases in interactive media, gaming, physical AI, and robotics that were previously impractical. The company targets a new generation of developers building what it calls "real-time world models": AI systems that generate and update video environments continuously in response to input. Founded in August 2025 by Alberto Taiuti (CEO) and Bryce Schmidtchen (CTO) — former technical leads for the Apple Vision Pro AR/VR headset — the company is based in San Francisco's South Park neighborhood. The team of 16 includes engineers and researchers from Apple, Netflix, Meta, Google, Adobe, Replicate, and Microsoft. Jeffrey Katzenberg (WndrCo) joined as a board observer. In May 2026, Reactor emerged from stealth with $59 million in total funding, including a Series A led by Lightspeed Venture Partners.